Gas springs are used for suspension purposes in a large number of vehicles ranging from snowmobiles to large industrial trucks. Quite often the gas springs are provided with oil damping. The spring effect of a gas spring is based on the compression of gas, the pressure of the gas varying as a function of the compression. Gas springs usually comprise a cylinder which is closed at one end and in which gas is contained. A piston connected to a piston rod is movably arranged in the cylinder. The piston rod and the cylinder are mounted between two parts of the vehicle between which a spring action is desirable. When the spring is being used or when the ambient temperature rises, the temperature of the gas in the cylinder increases, which creates increased pressure on the gas and greater force is thus exerted on the piston. In the case where the gas spring also contains oil, which is the case in a gas spring with oil damping, also the expansion of the oil will contribute to the pressure increase. Correspondingly, a reduction of the temperature of the gas and the oil will result in reduced pressure in the gas and less force will thus be exerted on the piston.
The variation of the spring force in dependence of the gas temperature as described above may be acceptable as long as it is not too great. However, great variations in the spring force are undesirable as they will affect the behaviour of the vehicle on which the gas spring is mounted.